How can I force a job status to fail?

Change the Batch script to

	Code:
	@ECHO IF NOT EXIST C:\Users\....user path goes here...\Desktop\test.txt GOTO PRINT_ERROR ECHO File not found EXIT 0 :PRINT_ERROR ECHO ERROR EXIT 1

Then the previously referenced solution will work for you

	Code:
	var runInfo = Process.runAndWait("C:\\path\\to\\file\\mybatch.bat", 0); if(runInfo.getOutput().indexOf("ERROR") >= 0) makeJobFail; // this invalid command will make the job to fail